Smart terminals are generally equipped with various operating systems, and various functions may be customized according to users' requirements. Smart terminals commonly used in our daily lives include smart mobile terminals, smart vehicle-mounted terminals, smart televisions, smart wearable devices and the like.
With the development of smart terminal technologies, smart terminals having the underwater operation function are gradually coining into users' lives. For example, users may perform such gesture operations as tap, swipe and the like on the smart terminals underwater.
In practice of the present application, the inventors have found that: a capacitive touch screen is used as an input device for the gesture operations on the smart terminal, and in a normal usage environment, a dielectric medium of each capacitor node is air; and a finger touch to the touch screen may cause the capacitances of the capacitor nodes of the touch screen to vary, and thus touch detection may be implemented according to this feature. However, if the touch screen is operated underwater, the dielectric medium of each capacitor node becomes the water, of which the dielectric constant is greatly different from the air, where the dielectric constant of air is 1.000585 whereas the dielectric constant of water is 81.5. Therefore, relative to the case where the dielectric medium is air, the impedance between the capacitor nodes becomes smaller when the dielectric medium is water, and variation of the capacitor node before and after been touched is also different. Accordingly, if whether a finger touch is present is still judged in the same way as that in air, the position of the touch may not be accurately determined.
Therefore, how to accurately determine a touch position of a capacitive screen underwater is a technical problem in the related art to be urgently solved.